How do these two substances compare? explain. a. both substances are pure substances and can be classified as molecules. o2 is considered a compound, because it made up of two different elements, whereas h2o is not a compound. b. both substances are pure substances and can be classified as molecules. h2o is considered a compound, because it made up of two different elements, whereas o2 is not a compound. c. both substances are pure substances and can be classified as molecules. each one is also considered a compound, because they have elements bonded together. d. both substances are pure substances and can be classified as molecules. neither is called a compound because they have only one element in each molecule.

When the water vapor cools it condenses select a number that represents his process on the

A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.

For each of the compounds below, show that the charges on the ions add up to zero. a. kbr b. cao c. li(2)o d. cacl(2) e. alcl(3)